不同横向距离下双射流孔流动与冷却特性实验研究

Experimental study on flow and cooling characteristics of double-jet film-cooling holes at different spanwise distances

通过实验方式,在平板上对不同孔间横向距离(p/d=0,0.5,1.0,1.5,2.0)下的双射流气膜冷却结构进行了研究。使用七孔探针测量了孔下游不同截面处的时均流场,使用压力敏感漆(PSP)测量了平板表面的气膜冷却效率。孔间流向距离(s/d)为3.0。吹风比(M)为0.5,1.0,1.5,2.0,射流-主流密度比为1.0。研究了孔间横向距离对双射流间相互作用,及其流动和冷却特性的影响。结果表明,p/d=0时,孔间相互作用体现为压附效应,下游射流被上游射流压向壁面并保持贴附,气膜冷却效率对吹风比不敏感。p/d=0.5与1.0时,反肾形涡效应主导,两股射流均被压向壁面,气膜覆盖较好,冷却效率较高。p/d≥1.5时,压附效应基本消失,反肾形涡效应减弱,射流间距增加,气膜覆盖变差。

Double-jet film-cooling structures on a flat plate at different spanwise distances （p/d = 0, 0. 5,1.0,1.5,2.0） are investigated experimentally. The time-averaged flow field at several cross-sections in downstream of the holes is measured by a seven-hole probe, and the film-cooling effectiveness on sur- face of the flat plate is measured with pressure sensitive paint （PSP）. The measured results indicate that the streamwise distance （s/d） is 3.0, and the blowing ratio （M） is 0. 5, 1.0, 1.5, and 2.0 while the density ratio （DR） is 1.0. The interaction between the two jets, its influence on the flow and cooling characters are investigated. The results show that, as p/d = 0, the interaction between the holes is presen- ted as pressing effect, that is, the downstream jet is pressed on the wall surface by the upstream one and keeps attached to the surface, and the film-cooling effectiveness is not sensitive to blowing ratios; as p/d = 0. 5 and 1.0, the anti-kidney vortex effect dominates, both of the jets are pressed down on the surface, and the film coverage is good and the effectiveness is relatively high ; as p/d ≥ 1.5, the pressing effect al-most disappears, the anti-kidney vortex effect weakens, the distance between the jets increases, and the fihn coverage degrades.